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As a cyclist, you know you need to consume protein to help with recovery, muscle maintenance, and bone health. And if your goal is to build muscle, you definitely need protein to make that happen, especially after a weightlifting workout.
But does timing matter when it comes to the benefits of protein? Should you have it first thing in the morning? Or should you focus your protein intake to nighttime?
To get you to the answer, we sifted through the research to find out the advantages to sipping a protein shake before bed. Here’s what you need to know.
The Benefits of Having a Protein Shake Before Bed
For starters, protein is essential throughout the day. However, a systematic review published in the Journal of Science and Medicine in Sport in 2020 found that consuming 20 to 40 grams of casein protein about 30 minutes before you head to bed does indeed stimulate protein synthesis as you sleep. This held true whether participants did resistance training before or not. (The catch: This review only involved research on men, with benefits serving mostly healthy young men, and researchers do note that more studies are needed to confirm these benefits.)
While not measuring muscle size or strength, another small study of nine physically active women, published in Nutrients, suggests consuming 48 grams of casein protein about 30 minutes before bed and two hours after dinner may help improve metabolism by elevating your resting metabolic rate (or how many calories you burn at rest) the next morning.
Other research points to similar pay-offs of pre-sleep protein. A scientific review, published in the journal Frontiers in Nutrition in 2019, looked at 45 previous studies to see how to best ensure muscle growth and muscle maintenance. The researchers set out to answer: Would simply boosting your daily protein intake be enough to show benefits—or might you see even greater results if you timed it a certain way?
The researchers found that people who drank a casein shake with about 30 grams of protein right before bed on days they lifted and on days they rested for 12 weeks gained more muscle mass—about four pounds—and strength than those who drank a non-protein placebo.
Keep in mind, while many pre-sleep protein studies only examine casein, research suggests whey and even some plant proteins may have a similar effect to casein when it comes to muscle recovery. For example, one study published in Sports Medicine suggests consuming 45 grams of either whey or casein protein before bed may increase both mitochondrial and myofibrillar protein synthesis rates.
Also, even if resistance training wasn’t done prior to protein intake at bedtime in the studies, you still need strength training to stimulate muscle growth in general, which means weightlifting is still key to gaining the muscle benefits of protein. And while all this research sounds promising, there are a few other things to consider before making a protein shake before bed part of your regular practice.
The Importance of Protein Throughout the Day
If you want to ride faster and longer, you need muscle. And building muscle requires strength training and rest, as well as consuming enough protein. That protein intake can include having a protein shake before bed, but you also want to eat the macronutrient in increments throughout the day.
Science has determined a dietary reference intake for both men and women when it comes to protein. Adults assigned female at birth require 46 grams per day while those assigned male require about 56 grams per day. Endurance athletes typically need more, though, up to 1.8 grams per kilogram bodyweight (or about 0.82 per pound) to maintain or build muscle. For a 150-pound person, that’s about 123 grams of protein per day.
As for how to make sure you get enough of the macronutrient throughout the day, most experts suggest having 20 to 40 grams after a workout to help with recovery. This may be after an evening workout and before bed—in which you’ll get that protein synthesis to kick in while you sleep—but if you work out in the morning, you still want some protein soon after your sweat session.
“Dietary protein consists of individual amino acids, which are the building blocks of skeletal muscle tissue,” Tim Snijders, Ph.D., lead author of the 2019 Frontiers in Nutrition study and assistant professor at Maastricht University, tells Bicycling. Plus, he adds, resistance exercise increases muscle protein synthesis, or the rebuilding of muscle tissue. Together, the two create an important one-two punch for muscle growth.
So if you want to eat protein throughout the day, especially after workouts, why is it so important to consume protein right before going to sleep? According to Snijders, food isn’t usually ingested during the night when you’re asleep, making this period of time the longest your body goes without eating each day. Without food in your system, no protein goes to your muscles and no protein synthesis occurs.
The Downsides to Drinking a Protein Shake Before Bed
If you’re worried about drinking a protein shake before bed and gaining weight or ruining your sleep—don’t fret. “All protein that is ingested prior to sleep is used for protein synthesis,” Snijders says. “When exercise is performed earlier that evening, a large part of ingested protein is directed to muscle protein synthesis and is not stored.”
In fact, Snijders adds, he and his researchers didn’t observe any gains in fat mass when young adults consumed protein before bed. Likewise, no studies they reviewed found that participants had trouble falling or staying asleep when consuming casein before bed.
The most important thing: Pay attention to how having a protein shake before bed affects you. If you find that the beverage leads to disturbed sleep, or it just doesn’t settle well, know that you’ll still benefit from having protein throughout the day.
Danielle Zickl is a freelance writer who has 10 years of experience covering fitness, health, and nutrition. She's a graduate of Ithaca College. You can find her work here on Women's Health, and in many other publications including PS, SELF, Well+Good, Runner’s World, Outside RUN, Peloton, Men’s Fitness, and more.
Dr. Namrita Brooke is a full-time endurance sport coach and sport nutritionist advising active individuals and amateurs to professional athletes. She is also an adjunct professor in the Department of Movement Sciences and Health at University of West Florida. Professionally, she also serves on the Board of Editors of the Sports Nutrition Care Manual and remains involved in nutrition and exercise-related research, student mentorship, and coach development. Namrita's personal athletic experience ranges from ultra-endurance mountain biking to off-road triathlon, cross-country mountain bike racing, gravel cycling, duathlon, cyclocross, running, and trail running. Her research background includes hydration and sports drink research, and the interaction of nutrition, physical activity, and the brain.
